Process of peptisating colloidal elements.



HANS KUZEL, OF BADEN, NEAR. VIENNA, AUSTRIA-HUNGARY.

PROCESS OF PEPTIlISATING COLLOIDAL ELEMENTS.

Specification of Letters Patent.

Patente d Sept. 29, 1908.

Application filed March 26, 1907. Serial No. 364,734.

must be again reduced, or they must be esse's of Peptisating ColloidalElements, of' which the following is a full, clear, and exactdescription, such as will enable others skilled in the art to which itappertains to make and.

use the same.

It is well known that colloidal or pseudosolutions of all substances canbe .coagulated for instance by the addition thereto of an electrolyte,the coagulum soobtained being called according to Grahams nomenclature agel, as contradistinguishedfrom the solid sol, which in many cases maybe obtained from the colloidal or pseudo solutions by cautiousevaporation. The essential difference between the gel and the solid solis that the latter maybe directly dissolved in an imbibition liquidwhile the ge is not directly soluble in an imbibition liquid.

Hence a colloidal solution or a pseudo-solution or a colloidal susension may 'be considered as a solution 0 a sol.

In case water is the imbibition liquid in which the .solis soluble, thesol is called a hydrosol and the gel obtained from a solution of thishydrosol is called a hydrogel.

In case alcohol is the imbibition liquid, the

, sol and gel are called alcosol and alcogel converted into sols byimperfectly irreversible sols "lating the corresponding sols,-say bymeans of electrolytes could not be rendered soluble in imbibitionliquids or rec'onverted into sols by such special treatment with certainreagents or in other words could not be peptisated. Therefore the gelsof pure metals were called perfectly irreversible sols.

To obtain from such non-peptisable gels colloidal solutions, a metalsalt must first be formed from them, and from this the metal atomized bymeans of the voltaic are, ac cording to Bredigs or Svedbergs methods(compare Zsigmondy Erkenntnis der Colloide chapter Einige VVorte fiberGelbildung, page 176 et seq.)

I have found that the refractory elements: chromium, molybdenum,uranium, tungsten, vanadium, tantalum, niobium, titanium, thorium,zirconium, boronand silicon constitute exceptions to this rule, as theirgels are very easily peptisated. According to my invention I peptisatethe gels of the refractory elements above named by treating them withsmall quantities of solutions of alkaline reaction, such as ammonia, orammonium bases or fixed alkalies (caustic soda or potash) or their:carbonates. If for in-v stance to the gel of tungsten obtained say byprecipitating the colloidal solution of tungsten by a just sufficientquantity of an electrolyte or by electric atomizing of metallic tungstenin the presence of an electrolyte, ammonia or an ammonium base, forinstance, methylamin, is added, until after repeated shaking, itjustclearly smells thereof, or red litmus paper is blued, then after ashort, time on the addition of a sufficient uantity of pure vdistilledwater, the entire ge passes into a colloidal or pseudo solution, showingall the characteristics of a colloidal solution. Particularly on beinfiltered it goes through the filter without leaving on the same anotable residue, the filtered liquid being dark colored and inklike inap earance, but per fectly transparent in thin ayers;'on irradiation bya ositive lens, the liquid shows the Tyndall e ect, thatis to say, acone of light is seen in the liquid (similar to that seen under the sameconditions in fluorescent solutions), the light emitted bythe same beingpolarized. The small quantity of residue remaining on the filteringpaper is retained by, the same perhaps by absorption; The

sols thus formed by peptisating the gels are transformed by a longer orcontinued action of ammonia, into gels again by Lpectinizing.

By small quantities of fine alkalies, for

instance, caustic alkalies or alkali carbonates,

'the same phenomena are produced; their con centration must however bemuch lower than that of ammonia. Thus for instance, when caustic soda is.used, a concentration of 0.05% is sufiicient. Such peptisated colloidalmetals have in a concentrated form a high agglomerating power for drypowders of any kind, for instance, metal powders and are designed to beused, in connection with such dry metal powders by mixing them with thelatter, whereby a plastic mass is obtained,

which is then brought to the desired shape, for instance, into that ofthin threads. The bodies thus' obtained are then dried and. finallyheated to a suitable temperature not exceeding the melting temperatureof the elements used. By such heating the colloid is reconverted intothe ordinary metallic state and forms what is usually called a solidsolution with the constituent added. in a pulverulent state.

If'powdered lead is added to colloidal metals peptisated as abovedescribed and the plastic mass thus obtained is molded,

dried and heated as above indicated, projectiles of high specificgravity and great toughness are obtained.

I claim as my invention: A process for pe tisating coagulated colloidsof refractory el tions of alkaline reaction and stoppin such tially asdescribed.

In testimony whereof I have signed my name to this specification, in thepresence'of,

two subscribing witnesses.

HANS KUZEL. Witnessesz,

- T. GEORGE HARDY,

ALVESTO S. HOGUE.

